#include <ESP8266WiFi.h>
#include <SoftwareSerial.h>
#include <PubSubClient.h>
#include <dht11.h>//引入DHT11库

SoftwareSerial mySerial(13, 12); // RX, TX

/********************###定义###********************/
dht11 DHT11;//定义传感器类型
#define DHT11PIN 2//定义传感器连接引脚。此处的PIN2在NodeMcu8266开发板上对应的引脚是D4
 
/********************###子函数###********************/
double Fahrenheit(double celsius)
{
  return 1.8 * celsius + 32; //摄氏温度度转化为华氏温度
}
 
double Kelvin(double celsius)
{
  return celsius + 273.15; //摄氏温度转化为开氏温度
}

// Update these with values suitable for your network.

const char* ssid = "1122";//wifi账号
const char* password = "11111111";//wifi秘密
const char* mqtt_server = "159.75.88.181";//mqtt服务器

WiFiClient espClient;
PubSubClient client(espClient);
long lastMsg = 0;
char msg[50];
int value = 0;

void setup_wifi() {

  delay(10);
  // We start by connecting to a WiFi network
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  randomSeed(micros());

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

/**
 * 消息回调
 */
void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print((char)payload[0]);
//  Serial.print("Message arrived [");
//  Serial.print(topic);
//  Serial.print("] ");
//  for (int i = 0; i < length; i++) {
//    Serial.print((char)payload[i]);
//  }
//  Serial.println();

//  // Switch on the LED if an 1 was received as first character
//  if ((char)payload[0] == 'o') {
////    digitalWrite(BUILTIN_LED, LOW);   // Turn the LED on (Note that LOW is the voltage level
//    // but actually the LED is on; this is because
//    // it is active low on the ESP-01)
////      Serial.print('o');
//      mySerial.print('o');
//  } else if ((char)payload[0] == 'f') {
////    digitalWrite(BUILTIN_LED, HIGH);  // Turn the LED off by making the voltage HIGH
////      Serial.print('f');
//      mySerial.print('f');
//  } else if ((char)payload[0] == 'a') {
//      mySerial.print('a');
//  }else if ((char)payload[0] == 'b') {
//      mySerial.print('b');
//  }

}

/**
 * 断开重连
 */
void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Create a random client ID
    String clientId = "ESP8266Client-";
    clientId += String(random(0xffff), HEX);
    // Attempt to connect
    if (client.connect(clientId.c_str())) {
      Serial.println("connected");
      // Once connected, publish an announcement...
      client.publish("dht11Topic", "hello world");
      // ... and resubscribe
      client.subscribe("51Topic");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}

void setup() {
  pinMode(BUILTIN_LED, OUTPUT);     // Initialize the BUILTIN_LED pin as an output
  Serial.begin(9600);
  mySerial.begin(9600);
  setup_wifi();
  //配置mqtt服务器地址和端口
  client.setServer(mqtt_server, 1883);
  //设置订阅消息回调
  client.setCallback(callback);
}

void loop() {
  //重连机制
  if (!client.connected()) {
    reconnect();
  }
  //不断监听信息
  client.loop();

  long now = millis();
  if (now - lastMsg > 5000) {
    DHT11.read(DHT11PIN); //更新传感器所有信息
 
//    Serial.print("humidity: ");
//    Serial.println((float)DHT11.humidity, 2);
//   
//    Serial.print("temperature: ");
//    Serial.println((float)DHT11.temperature, 2);
   
//    Serial.print("当前温度 (℉): ");
//    Serial.println(Fahrenheit(DHT11.temperature), 2);
//   
//    Serial.print("当前温度 (K): ");
//    Serial.println(Kelvin(DHT11.temperature), 2);
    //每5s发布一次信息
    lastMsg = now;
    ++value;
    snprintf (msg, 50, "temperature: %f,humidity: %f", (float)DHT11.temperature, (float)DHT11.humidity);
//    Serial.print("Publish message: ");
//    Serial.println(msg);
    client.publish("dht11Topic", msg);
  }
}
